Does anybody know what would of caused this sort of damage of my big end shells?

 

according to the haynes manual its "fatigue failure"

 

badly fitted bearings or lack of oil at some point

 

could be severall things that !
oil starvation, oil pump packed in?
wrong size bearings fitted?

strange to see all of them the same! normally u would just get one or two not all four?
unless like as said above the oil did starve all four big ends?
whats the mains like?

 

lubrication failure by the looks of it. did the oil light come on?
what does the crank look like?

 

On saturday i replaced the oil pump, felt alright but hard to tell if it was doing its job. I measured the journal on 4 and it was in the standard size tollerances (sp?) and the bearing had the size std on them. i was hoping it was just number 4 but they all seem the same. The engine has only been run for about 15 mins at most oil pressure when from 40 psi down to about 10 ish. i checked two of the big end shells (number 2 and 3) before i ran it. they were fine a little bit worn but no way near as bad as they were when i took them out on saturday. I haven't checked the mains (hopeing they are alright.) All the journals looks fine, some of the white metal was on them but i got rid of it and they were all in the standard tollerance (sp?).

I have fitted new big end shells and i hope the mains are ok. i haven't had a chance to run it as the weather has been crap.

 

no oil.....seem it before when the interior of the engine has been cleaned with a normal rag...then the fibres blocked up the oil pick up...lasted about 10 - 15 minutes....i'd check the pump as well as what's been said above....

 

As above the same thing happened to a m8 of mine
blocked the pick up pipe

 

Got it running today, no rumbing, good oil pressure, looks like i've got away with the mains.

 

you fitted new shells without getting a crank re-grind?

suerly they wont last very long, if at all, going by the state of them i'd imagine the crank will atleast be scored?

 

TBH honest mate, abit of white metal was stuck on the journals. I removed it but abit of careful polishing and the journals were fine no scoring at all. The engine was run for long at all. It was oil pump failure. New shells, new oil pump. 100 psi when cold going to 70 psi when hot. just have to run it in abit and hope the oil pressure doesn't drop too much or else i suspect the mains are damaged.

 

Sounds like you got away with it then

 

i'll give it 1000 miles and it will be the same specially if u didn't check the mains?

 

If it does, never mind, i've got a spair bottom end so i'll just stick that in and rebuild the one that was in there.